Aggregate functions return a single value, calculated from values an expression passed as parameter to the function evaluates to for all selected rows.
| AVG() | Returns average value |
| COUNT() | Returns number of rows |
| MAX() | Returns largest value |
| MIN() | Returns smallest value |
| SUM() | Returns sum |
| FIRST() | Returns value of the given expression evaluated for the first row of the query's result set |
| LAST() | Returns value of the given expression evaluated for the last row of the query's result set |